NORTH CONWAY — The search for Abigail Hernandez entered its fourth day Saturday, on her 15th birthday.

By day's end, no one was celebrating as law enforcement officers reported no substantive developments in the case.

"Unfortunately, we still have nothing new to report," Conway Police Chief Ed Wagner said during the latest news conference during the ordeal, held shortly after 6 p.m. Saturday in front of the Conway police station.

He added members of the Conway police, FBI and New Hampshire State Police have conducted many interviews and followed up on leads and tips.

"We're asking the public's help, nothing is too small to report," he said.

Appearing in front of news cameras for the first time since her daughter disappeared, Abigail's mother, Zenya Hernandez, made an emotional plea for her daughter to come home and asked anyone who may have noticed a change in Abigail to come forward.

"Abby, please come home. We miss you so badly. I think about you all the time. We want you back with us, please. We love and miss you," Zenya said through tears.

"Happy birthday, Abby," she said, before asking anyone who noted a change in her daughter's behavior or knows anything about her whereabouts, to "come out and let us know."

At the news conference, Wagner and New Hampshire Fish and Game Department Maj. Kevin Jordon both urged anyone with any information, no matter how insignificant a detail may appear, to call the Conway Police Department at 356-5717, or the FBI tip line at 1-800-CALL FBI or leave information on line at tips.fbi.gov.

Abigail's mother spoke briefly when reached at home earlier in the day.

"It's been tough for us," Zenya Hernandez said. She said officials have asked her not to talk to anyone about the case, but she expressed confidence that law enforcement was doing everything it could to search for her daughter.

"They are doing whatever it takes to bring Abby back," she said.

Jordon said the search thus far has covered 1,000 acres over land, and the search from the sky has included flying over swamps, waterways and treelines.

"We're nowhere near done," he said of the search. "We're here to find Abby and bring her home to her parents."

However, thus far officials have found "no significant clues as to her whereabouts," he said.

Jordon said two incidents occurred Saturday that prompted the the state medical examiner to be called. One involved the "tragic loss of a hiker" close to the area, and another involved the recovery of old bone fragments in a case unrelated to this investigation, he said.

Kennett Middle School acting Principal Kevin Richard declined to discuss personal details about Abigail, but confirmed she was a student there for two years. Richard, who organized a prayer vigil on Saturday night at the middle school, said he has been keeping in touch with different people in the community.

"The community is just praying and hoping we find Abby," he said. The mood at the school is one of "genuine concern," he said, adding that as Chief Wagner had said the day before, "we just want Abby to come home."

"The school and the community are doing everything we can to help in any way we can," he said.

Paul Kirsch of the White Mountain Milers running club was among the volunteers who helped officers comb the trail area that runs under power lines. Kirsch knows the Hernandez family. Zenya is a club member and volunteer and has participated in running events in the past. Abigail's older sister, Sarah, is also a member of the running club. Kirsch's son is in Abigail's grade at the high school.

Kirsch said club members heard that Fish and Game needed volunteer searchers on Friday, so they pitched in.

"It was just looking for clues or anything. Nothing was found," he said.

Kirsch described Zenya as a great volunteer and mother.

"All I know is they are super nice, everyday people. Zenya is a super person, a super volunteer and a super parent from as far as I can tell," he said. "All of our hearts go out to them. We'll help in any way we can."

As for what he's hearing from school, he said the students are upset and most likely heard the helicopters over Conway and North Conway all day long on Friday.

"All of us are just hoping for the best outcome," he said.

Abigail was last seen Wednesday afternoon on her way to Village Way from Kennett High School, authorities have said. Hernandez was a student at Kennett Middle School for two years before entering high school this year. She is described as 5-feet 4-inches tall, 118 pounds, with a thin build. She was last seen wearing black yoga pants, black boots and a gray-striped sweater.

A New Hampshire State Police K-9 unit tracked Abigail to her home on Wednesday afternoon, but she was not there when her mother arrived later. On Friday, officers from the FBI, Fish and Game, the Conway Police Department and the state police were joined by volunteers in searching areas including Puddle Pond, a small pond near the high school, and the trail underneath the power lines that lead from the high school to the Walmart on North-South Road.

Police presence was heavy in the Conway area on Saturday, with a half-dozen state police cruisers seen headed toward the Conway station in the early afternoon. At the police station, individuals delivered a stack of pizzas and cartons of bottled water and soda for lunch. Wagner declined to comment on the exact search locations on Saturday, adding only that teams were in the Cranmore area. On Friday, officers searched on land and from the air in low-flying aircraft.

Carroll County Attorney Robin Gordon has been carefully monitoring the case, which is still classified as a missing-person investigation.

She said all the officers involved are "working like dogs" to bring Abby back home.